Since April, the environmental organization Greenpeace has had a bull’s-eye on Apple in its campaign to clean up the Internet “Cloud” that stores our music, apps, and photos. It’s accused Apple of using high-carbon “dirty fuels” like coal to power its new data center in North Carolina and has used dramatic pranks and slick videos to get consumers involved.

Last week, members of Greenpeace barricaded themselves in a giant iPod at Apple’s Cupertino headquarters and dressed as giant iPhones to demand a cleaner iCloud. Two days later, in a rare demonstration of transparency, Apple released a detailed statement explaining how its new data center would be 100% green. The whole drama made me curious to learn how the Cloud’s power source and growth could impact the environment.